This invention relates to printed circuits, and in particular, to a circuit which incorporates integral fuses at selected locations along the circuit conductors.
In today's competitive electronics market, manufacturers are placing additional emphasis on reducing direct labor costs and increasing product reliability. This emphasis is easily understood when it is realized that today's manufacturers purchase all of their components and most of their subassemblies from outside suppliers. Their main task is to assemble and interconnect all components and subassemblies found within their product. The majority of these components are still interconnected using wire. However, a growing trend is the use of flexible printed circuits for such interconnections.
Each such circuit is custom designed to a specific length, current carrying capacity and geometric shape to fit the package. This circuit is, in fact, an engineered component and, as such, can be incorporated into volume assembly techniques as are other components. Flexible printed circuits are easily tested and quickly connected with no chance of wiring errors. For these reasons, the circuits are gaining wide acceptance with today's electronic manufacturers.
In an electrical circuit, it is desirable to have fuses at selected locations in the circuit runs to protect various electrical components from power surges. This is particularly so in the case of flexible printed circuits which establish electrical connections between many different components and subassemblies of electrical equipment such as data processing apparatus, communications apparatus, power supplies, diode amplifiers, etc.
Conventionally, such fuses are incorporated into the printed circuit as separate components or multiple fuse modules which must be connected electrically and mechanically to the circuit. However, prior fuses and fuse modules are relatively large and, as the conductor paths of printed circuits have become finer and more closely spaced, it has become increasingly more difficult to incorporate these fusible elements into the circuitry. It is desirable, therefore, to provide a better way of incorporating fuses into flexible printed circuits.
Accordingly, the present invention aims to provide a printed circuit having integral fuses present at selected locations along the circuit conductors.
Another object of the invention is to provide an improved fusible fine line printed circuit.
A further object of the invention is to provide a fusible flexible printed circuit which is resistant to motion stress during fabrication and installation.
Another object is to provide a flexible printed circuit with integral fuses whose fuse ratings can be set precisely.
Still another object of the invention is to provide a fusible flexible printed circuit which is relatively easy and inexpensive to make.
Another object of the invention is a fusible printed circuit which can accommodate materials, such as aluminum, that are not economically applicable to a conventional electroplating process.
Yet a further object of the invention is a fusible printed circuit able to provide for a controlled discharge in those applications requiring it.